Peristaltic pumps are used for creating a flow of a fluid in an elastic tubular conduit. These pumps have many medical and industrial applications.
In one form of peristaltic pumps, a rotor is used to rotate a plurality of eccentric cams. Each cam, in turn, intermittently collapses the elastic conduit at an initial contact point, and slides along the conduit over a short distance as the rotor turns. A second cam contacts the initial contact point, and the first cam is then released from the conduit as the second cam slides along the conduit. As this process is repeated, a flow of fluid in the conduit is generated in the direction of the sliding of the cams.
In another form of peristaltic pumps referred to herein as a “finger-type peristaltic pump”, a series of valves is aligned along an elastic conduit. Each valve comprises a “finger” that can alternate between two positions. In one position, the finger is extended from the valve so as to contact the conduit and to at least partially occlude the conduit at the point of contact. In the other position, the finger is retracted and does not contact the conduit. The series of valves is operated according to a temporo-spatial pattern so as to generate a flow in the conduit.
Commercially-available finger-type peristaltic pumps essentially include a hinged door, which is usually a rotatable member, adapted to continuously press the fluid conduit inserted in the body towards the valve fingers located in the body when in its closed configuration. This door is a frequent cause of failure in the pump's operation: the door is frequently opened while the pump in action, thus causing the conduit to fall out of place and cease pumping, opening the door and holding it open so as to insert the pipe requires three pairs of hands and thus can only be performed by two persons together, necessitating the presence of two medical personnel.
In addition, in this configuration the conduit pipe is exposed, i.e. is not wrapped or coated in any other material and is thus more vulnerable to contamination. The pipe is normally made of thin flexible silicon, which is worn down by the tip of the finger pump during extended use. Since it is common hospital practice to make use of a single pipe during the course of a patient's hospitalization, without replacing the pipe, during the course of use the pipe becomes increasingly vulnerable to puncturing, thus enabling contaminants (such as blood, HIV, Hepatitis virus, radioactive medicaments etc.) which may be present in the patients bloodstream or in the infusion being delivered, to accumulate on the outer surface of the pipe. If the pipe is inadvertently touched by unprotected hospital personnel, the user himself or his visitors, such contaminants may rapidly spread and be transmitted to a wider population.
The configurations currently available comprise three separate components: body, conduit and door. Inserting the conduit into the body, and then closing the door accurately requires considerable experience and manual dexterity, and can not normally be performed by chronically ill, physically limited or geriatric patients independently, thus requiring the constant attention of hospital personnel.
U.S. Pat. No. 5,395,320 to Padda et al. teaches a programmable peristaltic fingers infusion pump with an interchangeable variety of disposable tubing in commonly available sizes and types. The pump essentially comprises no less than two doors: an outer door (1) and an inner door (20), wherein the outer door (1) protects the inner door (20), which is kept in a close configuration by door latch (2).
U.S. Pat. No. 5,807,322 to Lindsey et al. presents a peristaltic pump unit that has a flexible infusion line (28) which is repeatedly compressed by a pusher (30). Line (28) is positioned in an elongated groove or channel (58) which acts to restrain sideways bulging of the line as it is being compressed by the pusher. The patent teaches that peristaltic pumps may be associated with a cassette which acts as a reservoir for the fluid to be pumped.
FR 2,753,236 to Ray et al. introduces a miniature peristaltic pump. The pump comprises inter alia a rotor, and a support piece equipped with a rounded-off portion (308) arranged in a substantially concentric manner to the rotor and against which, during operation, said rollers compress a flexible tubing (202) connected to a solution reservoir (201). Tubing (202) is inserted into circular opening (310), closed off by a cover (311). Thus again, slidable door member (311) ensures conduit (202) location directly adjacent to the pumping effecters (here rollers 110). Again the body and the door are integrally attached.
FR 2,632,529 to Gautier et al. teaches a drug injector with a removable reservoir in which the infusion liquid container may be inserted—held to control box by a pivoting arm engaged by head. The patent discloses a pump having a body (2) and rotatable pumping effecter (pump drum 7) towards which pipe (4) is pressed by means of maneuverable arm (10) being interconnected to body (2) by an hinge. Arm (10) is forcefully secured to body (2) by screw (16).